Reciprocating engine



Feb. 17, 1931. JQLJLIVINGSTON 1,793,107

RECIPROCATING ENGINE Filed Aug. 5, 1929 3 Sheets-Sheet l INVENTOR.

. NEY.

Feb. 17, 1931.

J. L. LIVINGSTON RECIPROCATING ENGINE Filed Aug. 5, 1929 3 Sheets-Sheet 2 I N VEN TOR.

l A TTORNE Y.

Feb. 17, 1931. J LIVINGSTON 1,793,107

REC IPROGA'I'ING ENGINE Filed Aug. 5, 1929' S Sheets-Sheet 3 Patented Feb. 17, 1931 UNITED STATES PATENT OFFICE JOHN 1'4. LIVINGSTON, OF DENVER, COLORADO, ASSIGNOR TO AMERICAN MOTOR COR" PORATION, OF DENVER, COLORADO, A CORPORATION OF COLORADO REOIFROOATING ENGINE Application filed August 5, 1929. Serial No. 383,496.

This invention relates to engines of the multi-cylinder type in which the reciprocating motions of the pistons is converted to the driven shaft through the intermediary of n a rotary cam wheel.

It is an object of the present invention to provide an engine of the above typp combining simplicity of construction with great practicability and eficiency in use.

to Another object resides in the provision of improved means to constrain the devices that engage with the rotary cam wheel to move 1n perfect alinement with the pistons without lateral deflection and without frictional resistance to the stresses imposed thereon by their action upon the cam.

A further object resides in providing means for varying the position of the pistons in the cylinders whereby to adapt the en- 29 gine for use at different altitudes by altering the compression ratio.

Another object is to provide simple and effective means for the operation of the valves of the engine by rotation of the shaft and still other objects will be found in details of construction and in novel and useful arrangements and combinations of parts set forth in the following description.

In the accompanying drawings in the several views of which like parts are similarly designated,

Figure 1 represents an end elevation of the engine,

Figure 2, a longitudinal section along the line2'2 Figure 1. 1

Figure 3, a section taken on the line 33, Figure 2,

Figure 4, a side view of the cam shown in Figure 3, looking in the direction of the arrow A, p I

Figure 5, a section on the line 5-5, Figure 2,

Figure 6, a section along the line 6-6, Figure 2, v

- Figure 7, an enlarged fragmentary section on the line 7-7, Figure 2,

Figure 8, a section along the line 88, Figure 7, 60 Figure 9, a development of the cam groove of the rotary movement-transmitting element of the engine,

Figure 10, a section on the plane indicated by the line 1010 in Figure 7,

Figure 11-, an enlarged section on the line 1111, Figure 5, and Figure 12, a section along the line 1212, Figure 10.

The cylinders 5 of the engine are grouped concentrically and symmetrically around the shaft 6, with their axes in parallel relation thereto. I

Pistons 7 fitted for reciprocation in the cylinders, carrying wrist pins 8 for their connection with driving-rods 9, and rollers 10 connected at the free ends of the rods engage in a circumferential groove 12 of a cam wheel 13 on the shaft.

The explosive mixture used in the operation of the engine is admitted to the cylinders through ports 14 and the spent gases are exhausted through ports 15. Valves 16 and 17 control the flow of fluids to and from the cylinders through their respective ports and these valves are alternately opened and closed at the proper times during the reciprocating movement of the pistons, by means of a camwheel 18 mounted on the shaft by means of a key 19.

The wheel 18 has upon its face two circular cam ridges 20 of undulating form that are engaged by the ends of rods 21 guided for lengthwise movement in openings of theframe of the engine. The rods connect at their gpposite ends with rocker levers 22 fulcrumed on standards 23 at the ends of the cylinder,

The opposite arms of the levers are pivotally connected with the stems 24 and 25 of the valves. Springs 26- coiled around the valve stems between the ends of. the cylinders and collars 27 on the stems function to return the valves to their closed position and to maintain the rods in contact with the respective ridges of the camwheel.

The engine frame hereinbefore referred to, includes a crankcase 29 enclosing the cam wheel and a housing 28 for the portion of the shaft within the circle of the cylinders.

The shaft is supported in bearings 30a, 30

and 31, and the cylinders which are bolted to the crank case are supported by the housing through the medium of suitable webs such as are indicated at 32 in Figure 2.

The housing is reenforced by a ring 33'and by enlargements 34, in which the guide openings for the rods of the valve movements are formed.

The cylinders'have, as usual, external fins for cooling purposes.

Before describing the construction of the cam wheel and the means for the support of the rollers 10 in operative relation thereto, it is to be understood that the engine as shown and described, is of the four stroke cycle type and that each cycle of four strokes is completed in one revolution of the shaft.

The endless groove of the cam wheel in which the rollers on the connecting rods travel, is with this object in view, composed of four undulations, as best shown in Figure 9, the pitch or distances between the extreme points of which measured across the drum, determine the strokes of the pistons.

It will be noted that these distances differ one from another with the object in view of differentiating the strokes of the pistons ac cording to their functions. Thus, the exhaust stroke may move the pistons substantially the entire length of the cylinders so as to completely scavenge the same after each explosion, the intake stroke may also belpractically the full extent of the piston movement and the compression and power strokes are comparatively shorter.

The ignition of the compressed fuel mixture in the cylinders is, as usual, effected through the medium of spark plugs and a suitable timing device, not shown in the drawings. The crank case may be filled ,with a suitable lubricant which greatly increases the eilicieney of the engine.

By changing the compression strokes of the pistons and thereby increasing or decreasing the compression ratio, the engine is readilv adapted for efi'icient operation at different altitudes, and these changes are readily accomplished by adjustment of the cam-wheel lengthwise of the shaft.

The cam-wheel is mounted for rotation with the shaft by means of a key 35 and its adjustment by sliding movement along said key may be readily effected through the medium of any mechanism suitable for operation froma point exteriorly of the crank case.

The mechanism shown in the drawings comprises a gear wheel 36 loosely encircling the shaft, a pair of pinions 37 meshing with the gear wheel 36, and a third pinion 38 likewise meshing with the gear wheel and having a crank 39 for its manual rotation. The last mentioned gear wheel is mounted for rotation wearer ed openings for their cooperation with screws 41 that connect with a ring 42 encircling the hub of the cam wheel 13. A. connection for conjoint lateral motion of the ring and the cam wheel is established by a series of balls 43.

It will be understood that the hub is free to rotate within the relatively stationary ring and that when it is desired to change the position of the cam wheel on the shaft in either direction, a rotary motion imparted to the gear wheel 36 by rotation of the crank 39 will cause rotation of the pinions 37 which in turn impart a longitudinal motion to the screws 41, thereby moving the cam wheel it along the shaft.

The adjustment of the cam wheel varies the position of the pistons in the cylinders so that the compression strokes may be changed to maintain a uniform efiiciency of the engine at different altitudes. This is of particular importance when the engine is used for propulsion of airships rising from the earth to high altitudes.

A distinctive feature of the invention resides in the provision of a hollow or tubular shaft. It will be observed that'the ends of the shaft are unobstructed and on airships equipped, with guns for use in warfare, the guns may be trained to fire projectiles through the hollow shaft while the engine is in operation.

Heretofore timing devices have been employed to prevent the projectiles from hitting the blades of the propellers and the use of such devices which frequently are unreliable, is made unnecessary by the provision of the hollow shaft;

It is apparent that the frictional resistance of the cam wheel to the impellent action of the rollers 10, subjects the rollers, the driving rods and the pistons to lateral stresses which if not negatived would render the engine inoperative. Ordinary guideways and crossheads are impractical because of their frictional contact during sliding movement of the one with relation to the other.

The following mechanism reduces the frictional resistance to the minimum and constrains the pistons to move continuall in a straight line in the axes of their cylin ers.

The mechanism accomplishes this result by preventing torque that might cause a twisting force upon the rollers as a result of lateral stresses and by keeping the line of thrust continually in the axis of the piston movement.

The rollers 10 are conical and the lines of their circumferential faces converge toward the axis of rotation of the cam, thereby assuring a constant rolling movement of the rollers while in contact with the converging walls of the correspondingly shaped groove of the cam wheel.

The'mechanism above referred to, comprises for each cylinder, a shoe 44 that has a sliding motion along a guide bar 45 of .arcual cross sectional form that is fastened upon the cylindrical wall of the crank case in parallel relation to the axis of the shaft. The shoe is concaved to fit the arcuate surface of the guide bar and thus may turn laterally upon the same.

. Rigidly fastened to the shoe is a hollow bearing-block 46 that is securely clamped inside the head of the driving rod 9. A spindle 47 is fixed in alined openings of the hearing block, and upon the protrudin end of the spindle, the roller 10 is rotata ly supported by medium of an anti-friction bearing 48.

Rotatable upon thevspindle inside the hollow bearing block is a swinging member 49' that holds the head of the driving rod against lateral motion without strain and which at the same time counteracts any tendency of the roller to move bodily about an axis outside of its axis of rotation on the head.

The member is to this end provided with a pin 50 that slides through a transverse opening of a cylindrical guide member 51 fitted for rotation in a bracket 52 fastened upon the inner circumferential surface of the crank case. This guide 51, it will be noted, takes up all lateral stress on the roller 10 by reason of its contact with the walls of the cam groove and thus aids in causing the roller to impart a rotary movement of the-cam without undue resistance.

The pin 50 by sliding movement in the roller takes up all stress that might cause twisting movement of the roller, as hereinbefore explained, and in order to support the member during its sliding motion and the rotary motion of the roller, it carries two rollers 53 that ride upon a track 54 inclined in opposite directions from the plane of theaxes of the spindle 47 and the guide 51.

The track is preferably formed on the same bracket that supports the roller.

Inasmuch as the operation of the engine has been referred to at different points in the above description, no further explanation is thought necessary to a complete understanding of the invention.

\Vhat I claim and desire to secure by Let ters Patent is: v

1. An engine of the character described comprising a shaft, a wheel on the shaft, having a cam-groove, a cylinder, a piston in the cylinder, a rod on the )iston, a roller on the rod, engaging in the groove, a fixed guide track, a shoe slidable on the guide track, in connection with the rod, an oscillating member pivoted on the rod, and a rotary guide for said oscillating member.

2. An engine of the character described comprising a shaft, a wheel on the shaft, having a cam-groove, a cylinder, a piston in the cylinder, a rod on the piston, a roller on the rod, engaging in the groove, a fixed guide track, a shoe slidable on the guide track, in connection with the rod, a rotary guide having a transverse passage, and an oscillating member pivoted'on the rod and slidable in said passage.

3. An engine of the character described comprising a shaft, a, wheel on the shaft, having a camgroove, a cylinder, a piston in the cylinder, a rod on the piston, a roller on the rod, engaging in the groove, a fixed track, a shoe slidable on the guide track, in connection with the rod, an oscillating member pivoted on the rod, a rotary guide for the oscillating member in its lengthwise motion, and a guide way supporting the member in its oscillating motion.

4. An engine of the character described comprising a shaft, a wheel on the shaft, having a cam-groove, a cylinder, a piston in the cylinder, a rod on the piston, a roller on the rod,.engaging in the groove, a fixed guide track, a shoe slidable on the guide track, in connection with the rod, an oscillating member pivoted on the rod, a rotary guide for the oscillating member in its lengthwise motion, a guide way to support the member in its oscillating motion, and a roller on the member, engaging the guide way.

5. An engine of the character described comprising a shaft, :1 wheel on the shaft, having a cam-groove, a cylinder, a piston in the cylinder, a rod on the piston, a roller on the rod, engaging in the groove, a fixed guide track, a shoe slidable on the guide. track, in connection with the rod, an oscillating member pivoted on the rod, a rotary guide for the oscillating member in its lengthwise motion, and guide ways supporting the member in -its oscillating motion, the guide ways converging to a point in the plane of the axes of rotation o the pivoted member and the rotary guide.

6. An engine of the character described, comprisinga shaft, 11 wheel on the shaft, having a cam-groove, a cylinder, a piston in the cylinder, a rod on the piston, a roller on the rod, engaging in the groove, an oscillating member pivoted on the rod, and a rotatable guide for said oscillating member.

7. An engine of the character described, comprising a shaft, a wheel on the shaft, having a cam-groove, a cylinder, a piston in the cylinder, a rod on the piston, a roller. on the rod, engaging in the groove,-a fixed guide track, a shoe slidable on the guide track, in connection with the rod, a pin on the shoe, for the rotarysupport of the roller, an oscillating member pivoted on the in, and a'rotary guide for the member in its lengthwise motion.

8. An engine of the character described comprising a shaft, a wheel on the shaft, having a cam-groove, a cylinder, a piston in the cylinder, a rod on the piston, a roller on the rod, engaging in the groove, a fixed guide track, a shoe slidable on the guide track, in connection with the rod, a pin on the shoe, for the rotary support of the roller, an oscil lating member pivoted on the pin, a rotary guide for the member in its lengthwise motion, and a fixed guide track supporting the member in its transverse motion.

In testimony whereof I have affixed my signature.

JOHN L. LIVINGSTON. 

